Goorha Flashcards
What symptoms are common with pancytopenia?
- Fever
- Mouth sores
- Shortness of breath
What is the most common etiology of aplastic anemia?
Idiopathic
What are the mechanisms that cause pancytopenia?
- Bone marrow failure
- Destruction of blood cells in the peripheral blood
What is bone marrow failure?
- Pancytopenia due to the failure of bone marrow to produce blood cells -> includes low RBCs (anemia), WBCs (leukopenia), and platelets
1. Symptoms of anemia: difficulty breathing, chest pain, fatigue
2. Symptoms of leukopenia/neutropenia: fever, infection, mouth sores
3. Symptom of thrombocytopenia: bleeding
What is the differential diagnosis of pancytopenia?
- Increased destruction: immune destruction, sepsis, hypersplenism
- Decreased production: myelodysplasia, marrow infiltrate, B12 deficiency, aplastic anemia, drugs, viruses, radiation
What are some typical causes bone marrow failure via hypo- and hypercellular bone marrow?
- Hypocellular: aplastic anemia
1. Congenital: Fanconi
2. Acquired: ideopathic, myelodysplastic syn (more often hypercellular), drugs/chemicals, radiation, viruses - Hypercellular: bone marrow infiltration
1. Hematologic malignancies, carcinoma, storage disorders, myelodysplastic syndromes, B12 or folate deficiency
What is aplastic anemia?
- Severe, life-threatening syndrome in which production of erythrocytes, ABCs, and PLT has failed
- May occur in all age groups, both genders
- Characterized by peripheral pancytopenia, and accompanied by hypocellular bone marrow
What is a primary mechanism of idiopathic aplastic anemia?
- Immune-mediated destruction of hematopoietic stem cells
What is the pathophysiology of aplastic anemia?
- Primary defect is reduction in, or depletion of hematopoietic precursor stem cells with decreased production in all cell lines -> leads to PERIPHERAL PANCYTOPENIA
1. May be due to quant/qualitative damage to pluripotent stem cell
2. Result of defective bone marrow microenvo
3. Form of cellular/humoral immunosuppression of hematopoiesis
What are the 2 congenital disorders associated with aplastic anemia?
-
Fanconi’s anemia: chromosomal instability syndrome
1. Disorder usually becomes symptomatic at about 5 y/o and is associated with progressive bone marrow hypoplasia
2. Congenital defects like small stature and skin hyperpigmentation also seen in affected ppl - Familial aplastic anemia: subset of Fanconi’s in which congenital defects absent (can even present at later age, including in adulthood)
What are treatment options for aplastic anemia?
- Immunosuppression
- Stem cell transplant
- Transfusion
What are the acquired causes of aplastic anemia?
- Most common is idiopathic: no hx of exposures to substances known to be causative agents of disease
- Ionizing radiation: hematopoietic cells particularly susceptible to destruction (300-500 rads can wipe it out, but recovery with sublethal doses)
- Chemical agents: incl. those with benzene ring, chemo, and certain insecticides
- Idiosyncratic rxns to some drugs: like quinacrine or chloramphenicol (not commonly used anymore)
- Infections: viral/bac like mono, hepatitis, parvovirus, CMV, and miliary TB
- Pregnancy: rare
- PNH: stem cell disease (PIG-A) in which membranes of RBCs, WBCs, & PLTs have abnormality making them susceptible to complement-mediated lysis
What lab findings are associated with aplastic anemia?
- Severe pancytopenia with relative lymphocytosis (b/c they live a long time)
- Normochromic, normocytic RBCs (may be slightly macrocytic)
- Mild to moderate anisocytosis, poikilocytosis
- Decreased reticulocyte count (HALLMARK FINDING)
- Hypocellular bone marrow with >70% yellow marrow (predominantly fat)
What is the tx for aplastic anemia?
- Should include:
1. Withdrawal of potentially offending agents
2. Supportive care (e.g., transfusion, ABs)
3. Immunosuppressive regimens: anti-thymocyte globulin, cyclosporine, steroids often effective at improving counts -> suggests auto-immune destruction of hematopoietic stem cells a primary cause of idiopathic aplastic anemia
4. Hematopoietic stem cell transplantation - If there is a problem, look at the drugs your pt is on first (to see if they are causing the aplastic anemia)
What is pure red cell aplasia?
- Characterized by a selective decrease in erythroid precursor cells in bone marrow -> WBCs, platelets unaffected
-
Acquired:
1. Transitory with viral/bac infections
2. Pts w/hemolytic anemias may suddenly halt erythropoiesis
3. Pts w/thymoma: T-cell mediated responses against bone marrow erythroblasts or EPO sometimes produced (potential TEST QUESTION) - Treatment: supportive care and immunosuppression
What is the primary difference between myelodysplastic syndrome and aplastic anemia?
- Presence or absence of neoplastic cells in the bone marrow